HP 5890 Series II Plus Reference Manual page 152

Detector Systems
Flame photometric detector (FPD)
Figure 7-11
140
120
100
80
Flow
ml/min
60
40
20
}
0
0
FPD Flows versus Supply Pressures
B. Detector Temperature. Detector heated zone temperature can have a
significant effect on sensitivity. If analyzing thermally labile or very
unstable compounds, a lower heated zone temperature may give the
best results. If analyzing compounds with high boiling points, the
detector temperature should be set at least 25 C but not > 300 C
above the final oven temperature (but not greater than 300 C!).
C. Quenching. Quenching can result to some degree if sulfur or
phosphorus peaks coelute with large hydrocarbon peaks. For many
applications, this effect can be reduced by better chromatographic
separation of peaks by varying the oven temperature program
conditions and/or column selection. In cases where there is a large
continuous hydrocarbon background, better selectivity of sulfur to
carbon may be obtained by adjusting the hydrogen or air (oxygen)
flow rate.
152
10 20
}
}
}
50 100 150
Pressure-psig
30 40
}
}
+
+
+
200 250 300
Pressure-kPa
50 60
+
+
}
= Hydrogen
= Nitrogen
= Oxygen
+ = Air
350 400 450
70
500